1. Field of the Invention
The invention relates to the mass delivery of messages. Particularly, the invention relates to a method for the delivery of area related messages in a mobile communication system.
2. Description of the Related Art
Mobile terminals provide an intriguing opportunity for the geographical segmentation of mass delivery messages. Examples of such messages comprise advertisements, informational notifications and emergency alert messages. The most important category is the emergency alert messages, which may be related to, for example, environmental catastrophes, terror attacks or police assistance requests identifying missing children or escaped convicts.
However, in existing mobile communication systems there is currently insufficient support for the delivery of area related messages with short delay requirements. In current technology the determination of the subscribers in a given area requires expensive procedures. It is usually required to form dump copies of any given location database. The dump copy is then analyzed using sequential brute-force search methods to determine the subscribers located in a given area at the time when the dump copy was formed. The sequential brute-force searches are required, because the location databases are not pre-indexed based on cells, location areas or other cell sets. Instead, the location databases are indexed using Mobile Station (MS) ISDN numbers (MSISDN) and International Mobile Subscriber Identities (IMSI). After the subscribers in a given location area have been determined, the subscriber identities may be provided to a server. The server takes care of the delivery of the messages to the subscribers via a messaging center such as a Short Message Service Center (SMS-C) or a Multimedia Message Service (MMS) center. Unfortunately, the whole process may take up to several hours during which the subscriber may have moved to an entirely different area.
Reference is now made to FIG. 1, which illustrates a Global System of Mobile Communications (GSM) network in the prior art. In FIG. 1 there is a Mobile Station (MS) 100, which communicates with a Base Transceiver Station (BTS) (not shown) via radio access. There is also a GSM/UMTS BSS 160, which is connected to a GSM/UMTS circuit switched core network comprising at least an MSC 150, a VLR 152, a GMSC 156, an HLR 154 and a CSE 158. GSM/UMTS BSS 160 is connected to MSC 150. VLR 152, stores information on the location areas of the subscribers registered to VLR 152. MSC 150 is connected to GMSC 156. There is also HLR 154, which stores subscriber data pertaining to the location of subscribers and their service data. GMSC 156 is also connected to PSTN 126. CSE 158 controls GMSC 156 and MSC 150 in the providing of IN services to the subscribers served by BSS 160. CSE 158 has also an interface to HLR 154, which allows the enquiring and modifying of service data in HLR 154. A plurality of standardized supplementary services is implemented directly by MSC 150, GMSC 156, VLR 152 and HLR 154. Examples of such services include call forwarding, call waiting, call transfer, call completion to busy subscriber, closed user group and call barring. In addition to these there may be a variety of vendor specific supplementary services implemented directly in these network elements. In the prior art, dump copies may be made of VLR and HLR databases.
Reference is now made to FIG. 2, which illustrates a prior art Universal Mobile Telecommunications System (UMTS), which supports also access via WLAN. In FIG. 2 there is shown a dual-system mobile station 200. The mobile station may also be a single system mobile station supporting only licensed band radio access. Mobile station 200 is capable of communicating both using an unlicensed band radio access and using licensed band radio access. There is an unlicensed band Base Transceiver Station (BTS) 202. BTS 202 is connected to a Customer Premises Equipment (CPE) 204, which is, for example, an access router. To CPE 204 is connected a Session Border Controller (SBC) 206. There may be a number of unlicensed band base transceiver stations, which are connected via CPE 204 to SBC 206. SBC 206 acts as a SIP proxy and hides the address space within the operator's network, which comprises at least IP access network 208 and the IMS network elements, from MS 200. User plane traffic to/from MS 200 goes via SBC 206. Session border controller 206 is connected to IP access network 208, which performs the packet transport for all user plane related data traffic.
In FIG. 2 there is also shown a licensed band radio access network 220 to which is connected a base transceiver station 221. Licensed band radio access network 220 is, for example, a 2G GSM radio access network or a 3G UMTS radio access network. A licensed band IP Connectivity Access Network (IP-CAN) functionality connected to access network 220 comprises at least a serving GPRS support node SGSN 222 and a gateway GPRS support node 224. SGSN 222 performs all mobility management related tasks and communicates with a Home Subscriber Server (HSS) 250. GGSN 224 provides GPRS access points to a media gateway 226 and to a Proxy Call State Control Function (P-CSCF) 230. GGSN 224 establishes Packet Data Protocol (PDP) contexts, which are control records associated with a mobile subscriber such as mobile station 200. A PDP context provides an IP address for packets received from mobile station 200 or any other mobile station that is connected to the licensed band IP connectivity access network 220. The GPRS is disclosed in the 3G Partnership Project specification 23.060.
The communication system illustrated in FIG. 2 comprises IP Multimedia Subsystem (IMS) functionality. The network elements supporting IMS comprise at least one Proxy Call State Control Function (P-CSCF), at least one Inquiring Call State Control Function (I-CSCF), at least one Serving Call State Control Function S-CSCF, at least one Brakeout Gateway Control Function (BGCF) and at least one Media Gateway Control Function (MGCF). As part of the IMS there is also at least one Home Subscriber Server (HSS). Optionally, there is also at least one Application Server, which provides a variety of value-added services for mobile subscribers served by the IP multimedia subsystem (IMS). The IMS is disclosed in the 3G Partnership Project (3GPP) specification 23.228. P-CSCF 230 receives signaling plane packets from GGSN 224. P-CSCF approves Quality of Service (QoS) allocation for the signaling plane PDP context opened in GGSN 224. In the signaling plane packet is carried a Session Initiation Protocol (SIP) signaling message. The Session Initiation Protocol (SIP) is disclosed in the Internet Engineering Task Force (IETF) document RFC 3261. The signaling message is processed by P-CSCF 230, which determines the correct serving network for the mobile station that has sent the signaling packet. The determination of the correct serving network is based on a home domain name provided from mobile station 200. Based on the home domain name is determined the correct I-CSCF, which in FIG. 2 is I-CSCF 232. I-CSCF 232 hides the topology of the serving network from the networks, in which mobile station 200 happens to be roaming. I-CSCF 232 takes contact to home subscriber server 250, which returns the S-CSCF name, which is used to determine the address of the S-CSCF to which the mobile station 200 is to be registered.
In FIG. 2 the S-CSCF determined for mobile station 200 is S-CSCF 234. S-CSCF 234 obtains information pertaining to mobile station 200 from HSS 250. The information returned from HSS 250 may comprise trigger information that is used as criterion for notifying an application server 252. Application server 252 may be notified on events relating to incoming registrations or incoming session initiations. Application server 252 communicates with S-CSCF 234 using the ISC-interface. The acronym ISC stands for IP multimedia subsystem Service Control interface.
The ISC interface is disclosed in the 3GPP specification 23.228. The protocol used on ISC interface is SIP. AS 252 may alter SIP invite message contents that it receives from S-CSCF 234. The modified SIP invite message is returned back to S-CSCF 234. If the session to be initiated is targeted to a PSTN subscriber, the SIP invite message is forwarded to a BGCF 240. BGCF 240 determines the network in which PSTN interworking should be performed. In case PSTN interworking is to be performed in the current network, the SIP invite message is forwarded to MGCF 242 from BGCF 240. MGCF 242 communicates with MGW 226. The user plane packets carrying a media bearer or a number of interrelated media bearers for the session are routed from GGSN 224 to MGW 226 as illustrated in FIG. 2 using line 262.
In case mobile station 200 communicates via the unlicensed band radio access, the packets are sent via BTS 202, CPE 204 and SBC 206 to IP access network 208. Signaling packets are received in P-CSCF 238. Based on a home domain name provided in the signaling packet P-CSCF 238 determines the correct I-CSCF, to which the signaling packet is to be sent.
In FIG. 2 the I-CSCF is I-CSCF 236. I-CSCF 236 queries the HSS 250 to determine the correct S-CSCF for mobile station 200. In this case S-CSCF 234 is determined. Depending on the called party SIP URI S-CSCF 234 determines whether the session is to be routed to a second S-CSCF or to a BGCF such as BGCF 240.
The same problems also appear whenever location information must be obtained from UMTS or GPRS location databases. The location databases are maintained, for example, in an SGSN, in a serving CSCF and in the HSS. The location databases may not be indexed using other attributes than subscriber identities. The use of these same location registers for subscriber filtering, based on area, may introduce additional load, which may be difficult to predict in system dimensioning.
The problem in prior art systems is that they do not address geographical segmentation of mass delivery messages. There are no current methods that would enable the timely filtering of the subscribers within a given area. For the purpose of this application, an area may be defined as a group comprising at least one cell. Examples of areas are GSM location areas, GPRS routing areas and UMTS system areas.